This invention is based on Japanese Patent Application No. 11-340705 filed Nov. 30, 1999 the contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a walking assistance device which is novel in construction and which is capable of facilitating or assisting ambulatory movement of a user afflicted with certain conditions, such as Parkinson""s disease.
2. Description of the Related Art
Patients afflicted with Parkinson""s disease experience reduction in number of spontaneous and autonomic movements, and suffer from walking disturbance, i.e., difficulty in ambulatory movement, for example. More specifically described, such Parkinson""s patients are incapable of taking a step or stride forward for initiating their ambulatory movement, so that they are subject to danger of falling forward with high possibility, even where the ambulatory movement of the patients are assisted by means of a general walking assistance device, such as a walking cane. That is, such a conventional walking cane is of no use for the Parkinson""s patients.
It is well known that the Parkinson""s patients can overcome their difficulty in ambulatory movement and walk, if the patient or patient""s brain is forcedly ordered to take a motion of stepping forward. Some patients can perform the normal walking reflexes, once they can start the ambulatory movement. In view of this specific symptom of the Parkinson""s disease, an assistive walking cane suitable for Parkinsonians has been proposed as disclosed in JP-A-11-309187. The disclosed cane includes an elongated body member and a movable plate member which is rotatably coupled to a lower portion of the elongated body member. The elongated body member is telescopically deformable by means of a coil spring incorporated therein. The rotatable plate member is alternately placed in its open and closed positions in association with the telescopic motion of the elongated body member. The disclosed cane is arranged such that when the user lifts the cane, the elongated body member is expanded due to the expansion of the coil spring, whereby the rotatable plate member is held in its closed position where the rotatable member is vertically oriented so as to extend substantially parallel to the elongated body member. When the user leans on the cane and the user""s load or weight accordingly acts on the elongated body member, on the other hand, the elongated body member is axially contracted due to the compression of the coil spring, whereby the rotatable plate member is held in its open position where the rotatable plate member is horizontally oriented so as to extend in a direction perpendicular to the axial direction of the elongated body member. The horizontally extending rotatable plate member projected in front of the user""s foot serves as a walking obstacle especially to Parkinson""s user of the cane. Encountering the walking obstacle stimulate the Parkinson""s user to step over the obstacle, enabling the Parkinson""s user to walk forward or start his or her ambulatory movement.
However, the conventional walking cane for the Parkinsonians as disclosed in the above-indicated document employs the coil spring for enabling the telescopic motion of the elongated body member which induces the alternative rotational displacement of the rotational plate member between its open and closed portion. Excessively large spring force of the coil spring causes insufficient contraction of the elongated body member, resulting in failure of placing the rotational plate member in its open position. On the other hand, excessively small spring force of the coil spring causes insufficient expansion of the elongated body member, resulting in failure of retracting the rotatable plate member to its closed position. Therefore, the conventional cane needs to be adjusted in its spring force depending on respective patient. If the spring force of the coil spring of the cane is adjusted to be a smaller value, the rotatable plate member is likely to suffer from insufficient retraction thereof to its closed position due to fatigue or sinking of the coil spring. It is significantly difficult to adjusting a suitable spring force of the coil spring, whereby the conventional cane for the Parkinson""s patient lacks of long-term stability of its operation condition. In particular, if the rotatable plate member is not duly retracted to its closed position due to the fatigue of the coil spring, the rotatable plate member is very much likely to protrude outwardly from the elongated body member in the generally horizontal direction, eventually possibly interfering the ambulating movement of the user or patient.
The present invention has been developed in view of the circumstances described above. It is therefore a first object of the present invention to provide a walking assistance device which is novel in construction and which is capable of alternately placing a longitudinal projection member, with high stability and reliability, in two operation positions, namely a xe2x80x9cretracting positionxe2x80x9d for accommodation of the projection member, and a xe2x80x9cprotruding positionxe2x80x9d for protrusion of the projection member into a path of movement of user""s foot. The projection member placed at a protruding position stimulates the user to step over the projection member, thereby effectively supporting ambulatory movement of the user afflicted with certain conditions, such as Parkinson""s disease.
It is a second object of the present invention to provide a walking assistance attachment which is attachable to conventional walking assistance devices or walking aids, such as a cane, for providing the ambulatory assistance device according to the present invention.
The first object may be achieved according to the following modes of the invention each of which is numbered like the appended claims and depends from the other mode or modes, where appropriate, to indicate possible combinations of elements or technical features of the invention. It is to be understood that the present invention is not limited to those modes of the invention and combinations of the technical features, but may otherwise be recognized based on the thought of the present invention that disclosed in the whole specification and drawings or that may be recognized by those skilled in the art in the light of the disclosure in the whole specification and drawings.
(1) A walking assistance device for assisting ambulatory movement of a user, including: a body member to which a weight of the user is applied; a shaft member fixedly disposed in a portion of the body member on the side of a walking surface so as to extend generally in a first horizontal direction; a longitudinal projection member disposed rotatably about the shaft member so as to extend in a direction perpendicular to the shaft member; and a mass member which is disposed so as to oppose to the longitudinal projection member in a diametric direction of the shaft member, and which is integrally formed with the longitudinal projection member. The mass member has a contact portion at which the device is brought into contact with the walking surface. The contact portion is offset from an axis of the shaft member by a predetermined distance in a second horizontal direction perpendicular to the first horizontal direction so that a ground pressure applied to the mass member produces a rotation moment which causes rotation of the longitudinal projection member about the shaft member in one direction. The longitudinal projection member is held in a protruding position where the longitudinal projection member protrudes outwardly from the body member generally in the second horizontal direction, owing to the rotation moment produced by the ground pressure applied to the mass member, and is held in a retracting position where the longitudinal projection member extends in a generally vertical direction, owing to gravity acting on the mass member.
In the walking assistance device according to the above mode (1) of the present invention, the contact portion of the mass member is subjected to the ground pressure, when the user put the walking assistance device on the walking surface, i.e., the ground, so as to lean on the walking assistance device. Since the contact portion of the mass member is offset from the axis of the shaft member by a predetermined distance in the second horizontal direction, the ground pressure applied to the mass member produces the rotation moment or a torque causing the rotation of the mass member and the longitudinal projection member about the shaft member in one direction, so that the longitudinal projection member protrudes outward from the body member so as to extend in the second horizontal direction. In this condition, the longitudinal projection member is provided in front of the user""s foot and served as a walking obstacle to the user, e.g., a Parkinson""s patient, effectively stimulating or inducing the user to step over the obstacle in order to overcome the obstacle. That is, the longitudinal projection member is effective to give a chance for the Parkinson""s patient to start his or her ambulatory movement.
Once the user lifts the walking assistance device, the mass member is released from the ground pressure, and then is subjected to gravity. The gravity applied to the mass member produces a rotation moment or a torque causing a rotation of the mass member and longitudinal projection members about the shaft member so that the longitudinal projection member is retracted toward the body member, whereby the longitudinal projection member is held in the retracting position so as to extend in the vertical direction on the side of the body member. Thus, the longitudinal projection member is effectively accommodated or retracted on the side of the body member, when the user lifts to carry forward the walking assistance device. In this arrangement, the longitudinal projection member does not interrupt the ambulatory movement of the user.
In particular, the longitudinal obstacle member is arranged to be held in the retracting position, by utilizing the rotation moment caused by the gravity acting on the mass member rather than the spring force of the spring member. This arrangement can provide a desired retracting force required for retracting and holding the longitudinal projection member in the retracting position with a long-term stability, while eliminating the problem of instability of the retracting force due to the fatigue or settling of the spring member which is conventionally employed to provide the required force. Further, once the walking assistance device is placed at the contact portion of its mass member on the walking surface, the ground pressure applied to the mass member cancels the gravity acting on the mass member. Excess ground pressure is further applied to the contact portion of the mass member, whereby the ground pressure produces the rotation moment which causes the rotational movement of the longitudinal projection member away from the body member, for holding the longitudinal projection member in the protruding position where the longitudinal projection member is horizontally oriented. This arrangement can also provide the rotation moment in the direction toward the protruding position with a long-term stability. Thus, the present invention is effective to provide the desired walking assistance device which is capable of alternately holding the longitudinal projection member in the retracting and protruding positions with long-term stability. It should be understood that the walking assistance device includes various types of walking aid such as canes, walking sticks, crutches, and walker device. Further, the shaft member may be directly disposed in the body member, or alternatively be indirectly disposed in the body member.
(2) A walking assistance device according to the above-indicated mode (1), wherein the walking assistance device is a cane, and the body member includes a longitudinal portion, while the shaft member fixedly disposed in one of axially opposite end portion of the longitudinal portion on the side of the walking surface so as to extend in a direction perpendicular to an axis of the longitudinal portion. In this mode (2), the walking assistance device in the form of the cane is made compact and portable, further facilitating ambulatory movement of the user.
(3) A walking assistance device according to the above-indicated mode (1) or (2), wherein the body member includes an accommodation recess for accommodating the longitudinal projection member which is held in the retracting position.
In the walking assistance device according to this mode (3), the longitudinal projection member held in its retracting position is effectively accommodated within the accommodation recess formed in the body member, eliminating or reducing an amount of projection of the longitudinal projection member outward from the body member. This arrangement is effective and reliable to prevent adverse effects of the longitudinal projection member held in the retracting position on the ambulatory movement of the user, resulting in improved safety and ease in handling of the device.
(4) A walking assistance device according to any one of the above-indicated modes (1)-(3), wherein the mass member has a spherical shape. In this mode (4), the mass member having the spherical shape permits that the ground pressure is applied to the mass member with high stability, leading to improved stability of operation of the walking assistance device. In addition, the spherical mass member is less likely to be caught in the other obstacles on the walking surface, and is less likely to injure the user upon contact with the user""s body, resulting in improved safety of the walking aid.
(5) A walking assistance device according to any one of the above-indicated modes (1)-(4), wherein the walking assistance device further comprises a stop member to limit an amount of rotational displacement of the longitudinal projection member relative to the body member in a direction toward the retracting position of the longitudinal projection member.
In this mode (5), the position of the mass member relative to the shaft member is suitably determined with high stability, when the longitudinal projection member is held in the retracting position, whereby a load center of the ground pressure applied to the mass member is determined with high stability, resulting in high stabilized generation of the rotation moment causing the rotation of the longitudinal projection member about the shaft member in the direction away from the body member, in other words, in the direction toward the protruding position. It should be noted that the stop member is not particularly limited to the member which is brought into contact directly with the longitudinal projection member to define the fully retracted position of the longitudinal projection member, but may otherwise be a member which is brought into contact with a portion on the side of the mass member in order to indirectly define the fully retracted position of the longitudinal projection member.
The second object indicated above may be achieved according to any one of the following forms of the present invention:
(6) A walking assistance attachment which is attachable to a walking assistance device for providing the walking assistance device according to any one of the above-indicated modes (1)-(5), the attachment including: the shaft member; and the longitudinal projection member disposed rotatably about the shaft member, the attachment being attachable to a portion of a body member of the walking assistance device, which portion is located on the side of the walking surface.
The attachment constructed according to the present invention, facilitates repair of malfunction of the walking assistance device by only changing or repairing the attachment, without requiring entire renewing of the walking assistance device. In addition, the attachment of the present invention can be fixed to the tip portion of a commercially available walking assistance device, such as canes, walking sticks, crutches, and walker devices, whereby the walking device provided with the attachment can exhibit the same advantage of the walking assistance device according to the present invention as described above.